After a cerebral infarction, a 64-year-old patient suffered from a very strange visual disturbance: all objects seemed 30% smaller to him. A distortion that he did not learn to compensate without difficulty in his daily life.
On December 28, 2017, a 64-year-old man named DN was urgently admitted to hospital with left-sided hemiplegia. Eleven days earlier, the patient had complained of temporary vision loss, after which an MRI was performed. This examination subsequently revealed a cerebral infarction in the right part of the occipital lobe and the parietal lobe. On December 28, doctors noticed that the infarction had spread to a larger part of the brain, causing hemiplegia.
Honey, the curtains have shrunk!
At that moment, DN notices a strange phenomenon: his entire environment seems to have shrunk. He accidentally buys an XL T-shirt that he thought was size M. doorsdoors he seems too small to fit through and the curtains in the living room seem so short to him that he imagines his wife has put them in the washing machine. All distances on the street are also shortened. Comparing the size of objects and people to those he remembers, he discovers that everything is 30% smaller. DN also notices that he has problems with the visual field on the left side. When he tries to read, he skips entire sentences because they are on the left page. On the other hand, he does not suffer from other neurological aftereffects: his memory and cognitive abilities are intact.
A deterioration of vision on the left side, compensated by a general narrowing of reality
To better understand this strange distortion, Nils van den Berg and his colleagues from the University of Amsterdam DN conducted several visual tests. In a study whose results were published in NeurocaseFor example, they asked him to estimate the size of several cubes, which he estimated on average to be 73% of their actual size. Further testing revealed that DN also had difficulty understanding shapes and objects movementmovement, but only in the left visual field. Doctors suggest that the overall ‘narrowed’ vision results from a compensatory phenomenon, where the right eye tries to compensate for poor vision in the left visual field. “ The result gives a smaller appearance to objects, but remains a symmetrical and comprehensive representation of reality », explains Nils van den Berg. The DN lesion in the right occipital lobe would explain the distortion of the left visual field, with the latter being projected into the right hemisphere.
Micropsy and “Alice in Wonderland”
The disease that DN suffers from is rare but not unique: it is called metamorphopsia, a visual disorder characterized by distortion of images. There are different kinds. That of DN, in which objects appear smaller, is micropsy. There is the opposite form, macropsia, where objects are enlarged. In the ” syndromesyndrome byAlice in Wonderland “Patients suffer from dissociation, which causes them to believe that their own limbs are elongated or deformed. Described in the scientific literature, these cases usually follow concussionsconcussionsbut their exact origin still remains very unclear.
Three months after his stroke, DN is doing better. He is gradually regaining the use of his left arm. On the other hand, he continues to see the world as smaller, but adapts to it. He compares unknown objects with known ones to estimate their size, and while cycling or driving a car carcarit remains attached close to the curb so as not to pose a risk of collision.